This invention relates to a device for providing strain relief to cables and, in particular, to a strain relief device for securing soft-jacketed cables of variable diameters carrying wires to telephone junction boxes for distribution to telephone equipment.
Telephone lines, which are carried by electrical conductors known as tip ring wire pairs, are generally aggregated at a particular point in a building prior to being distributed and connected to various types of telephone equipment, such as, for example, telephones, fax machines, modems etc. As the tip ring pairs enter the building as part of a multi-conductor cable, the individual tip ring wire pairs must first be broken out from the cable into individual wire pairs. This is normally accomplished in a junction box known as, for example, a building entrance protector (BEP), or network interface unit (NIU).
The multi-conductor cables are generally enclosed in stiff insulation jackets having variable diameters depending upon the particular application. Because these multi-conductor cables carry the tip ring wire pairs that will be connected to various types of telephone equipment, it is necessary to provide strain relief to the cable to insure that the tip ring wire pairs do not become disconnected or loose. Loose or disconnected wires in a junction box can cause serious malfunctions in telephone, computer, or network service requiring costly repair and maintenance service. In some instances, the cable is jacketed with a soft, malleable material, which can get crushed or pinched by a device utilized to provide strain relief. Thus, it is desirable to have a strain relief device capable of securing jacketed cables of varying diameters without causing the wires carried within to become pinched or crushed.
Presently, however, there is no efficient means for providing strain relief to soft-jacketed multi-conductor cables of variable diameters or shapes in a way designed to eliminate pinching in soft-jacketed cables. Thus, there is a need for a device capable of securing multi-conductor cables of variable diameters and eliminating pinches.
The present invention is directed at overcoming shortcomings in the prior art. The present invention comprises a base having a tubular extension with a compressible portion. A nut is mountable over the tubular extension and has an inner channel provided with a tapered region for constricting the compressible portion of the tubular extension.
The operation of mounting the nut over the tubular extension causes the tapered region of the nut to exert a compression force on the compressible portion, which deflects the compressible portion inward. In a preferred embodiment, the compressible portion is comprised of a plurality of deflectable arms having gripping pads mounted to the ends of each arm. Under a compression force, the gripping pads radially converge and secure the cable without pinching the wires within. Because the compressible portion can be gradually compressed by the nut to a desired compression, a range of variable diameter cables can be secured by the present invention. Thus, the need to use cable fastening devices constructed for specific cable diameters is eliminated, thereby improving efficiency and reliability in cable connections.
Other objects and features of the present invention will become apparent from the following detailed description, considered in conjunction with the accompanying drawing figures. It is to be understood, however, that the drawings, which are not to scale, are designed solely for the purpose of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.